Drainage Housewrap

ABSTRACT

A housewrap is a multi-layer drainage wrap. A nonwoven base web has a three-dimensional pattern embossed therein on one surface of the web. This embossed web is then extrusion coated with a polymer coating. The coating is extrusion-coated on to embossed side of the nonwoven base web. The nonwoven base web has the three-dimensionally embossed and coated side as its outward facing surface. The coated base web is then activated by stretching to provide moisture vapor permeance at a rate that allows a building to breathe. The result is a housewrap that is textured on both the inside and outside faces of the housewrap. The texture and weather resistive coating on exterior side facilitates both drainage of water off of the outside face of the housewrap and the circulation of air and moisture around and through the inside face of the housewrap and promotes a tighter seal and better adhesion to flashing tapes reducing further the points of entry for water into the structure.

The present invention is directed to a multi-layer housewrap thatprevents liquid water from passing through into a house, yet thehousewrap is still breathable to allow water vapor to pass through it.Further, the housewrap has a textured surface in the form of channelswhich allow water on the surface of the housewrap to drain down bygravity.

BACKGROUND

Many conventional housewraps are simply flat sheets of barrier material.With these wraps, a potential problem may develop in that water canbuild up between the outside of the wrap and the inside of the siding ofthe house. There can be nowhere for the water to drain, because it canbe blocked by the siding pressing against the housewrap. As a result,sometimes, the water may flow sideways to a window or door and causewater damage there. Therefore, even though a conventional flat housewrapmay possibly be an effective water barrier, ancillary problems mayarise.

Some housewraps have been developed that have bumps molded on orembossed in the housewrap substrate. The bumps define channelstherebetween that can allow water drainage downwardly behind the siding.In some cases, the bumps themselves are porous materials that allowwater to gather in the material. If a significant amount of water buildsup in the bumps themselves, then again, other possible moisture problemsmay arise between the housewrap barrier and a siding. It is also moredifficult for flashing tapes to adhere and provide a tight seal as thesurface that the flashing is sealed to is a porous mat below the tape.This area can provide an entry point for water to breach the flashingtape by wicking in underneath the tape.

SUMMARY

Accordingly, it is an object of the present invention to overcome thedrawbacks in existing housewrap products by providing a drainage andbreathable housewrap.

In one example, a drainage housewrap comprises a nonwoven base webhaving a three-dimensional pattern pressed therein to form channels on asurface of the base web, and a coating bonded by extrusion coating tothe surface of the base web after the three-dimensional pattern ispressed in it. The coating comprises a mixture of a polymer and calciumcarbonate particles, and the coated base web is activated by mechanicalstretching of the coated base web in order to create micropores in thecoating on the base web. The three-dimensional pattern pressed into thebase web may create two sets of channels that are substantiallyperpendicular from each other. The polymer portion of the coating maycomprise polyethylene or polypropylene. The three-dimensional patternmay be in the shape of oval half-bubbles. The oval half-bubbles may bepositioned in alternating rows such that a long axis of each row of ovalhalf-bubbles is perpendicular to the long axis of each adjacent row ofoval half-bubbles. The calcium carbonate may comprise 35-70% by weightof the coating.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a portion of the side of a house withhousewrap mounted thereon.

FIG. 1A is a perspective view of an example of the coated, outside faceof a housewrap as described herein.

FIG. 1B is a perspective view of an example of the uncoated, inside faceof a housewrap as described herein.

FIG. 1C is a pair of side views of a prior art housewrap and housewrapas described herein when mounted between a house structural board andhouse siding.

FIGS. 2A-2E are top views of portions of housewrap as described hereinillustrating different patterns and orientation of patterns embossed inthe housewrap.

FIG. 3 is a schematic view of the process of coating the polymer on thebase web of material.

FIG. 4 is a side, cross-sectional view of the housewrap film aftercoating and activation.

FIG. 5 is a schematic view of the complete process of coating andactivating the housewrap film.

FIG. 6 is a front view of an example of a building window that hashousewrap mounted around it and flashing tape applied around the window.

FIG. 7 is a side, cross-sectional view illustrating the seal created bythe installation of a flashing tape onto the housewrap.

DETAILED DESCRIPTION

The housewrap described herein is a multi-layer drainage wrap. Anonwoven base web has a three-dimensional pattern embossed therein onone surface of the web. The nonwoven base web has thethree-dimensionally embossed and coated side as its outward facingsurface. The coating is extrusion-coated on to the embossed side of thenonwoven base web. The coating is then activated by stretching after thecoating and cooling of the coating on the base web. The result is ahousewrap that is textured on both the inside and outside faces of thehousewrap. The texture facilitates both drainage of water off of theoutside face of the housewrap and the circulation of air and moisturearound and through the inside face of the housewrap.

Each component will be discussed separately herein. There can beadditional components that may be added depending on the application andintended environment where the housewrap is used.

The nonwoven base web is a substrate of nonwoven spunbonded polymerfibers. The fibers that may be used include polyethylene, polypropylene,polyester, nylon, polyvinyl chloride, bicomponent fibers and mixtures oftwo or more of the foregoing. In one example of the present web, thebase web has a weight of 8-120 g/m2, or 90-110 g/m2, or 95-105 g/m2, orin one example, about 100 g/m2. The thickness of the base web beforefurther processing is 0.0025-0.030 inches, or 0.003-0.020 inches, orstill further 0.005-0.012 inches. This thickness is the lofted thicknessof the nonwoven web before any embossing of a pattern on or extrudingany coating thereon.

Next, the nonwoven base has a bubble pattern embossed therein by passingthe nonwoven base through heated nip rollers. The surface of one of therollers is flat while the second opposing roller has a textured patternto create half-bubbles on the surface of the embossed nonwoven base. Theresulting pattern is essentially in the form of half-bubbles. Thehalf-bubbles may be round or oval or square or triangular or any othershape, whether symmetric or asymmetric. In one example, the half-bubblesare embossed in rows. The half-bubbles may be oval-shaped with the longaxis of the oval at about 45 degrees to the perpendicular of the wrapwhen installed on a building. The alternating rows of half-bubbles maybe 45 degrees in the opposite direction such that the adjacent bubbleson neighboring rows are 90 degrees offset from each other. The rows ofhalf-bubbles may be matching rows in that there are equal numbers ofhalf-bubbles that are spaced out equally in neighboring rows. In thisformat, channels are created perpendicular to each other so thatregardless of how the housewrap is installed, there is a verticaldrainage channel created.

The embossed web has a thickness of about 0.0015 to 0.060 inches, in oneexample about 0.008 inches, where compressed between the half-bubbles.The full height/thickness of the web with the half-bubbles is about0.015 to 0.05 inches, in one example 0.032 inches at its maximumthickness of the web. The area size of the half-bubbles is variable. Thelength may be about 0.1 to 4.0 inches, in one example 0.65 inches withthe width being about 0.1 to 0.5 inches, in one example 0.35 inches inthe oval example. For a multi directional installation there needs to begaps/channels between the raised areas allowing for water to flowdownward by gravity through the gaps. For a mono directionalinstallation, the raised areas can be the full height of the web (in astriping pattern). Also, the embossed pattern half-bubbles may beoriented in direction in multiple ways that encourage or direct waterdrainage down the face of the housewrap once installed. When taking intoaccount the entire surface area of the housewrap, the raised, embossedarea comprises from about 25% to 75%, in one example about 50% of theentire surface area of the housewrap.

Next, the embossed, nonwoven base web has a coating applied to it byextrusion coating. The molten coating material is applied by nip rollerto the base web and then quenched to bond the coating onto the web. Theheated coating material allows the intertwining of the molten materialinto the nonwoven web. Importantly, this means that no adhesive isrequired to attach the coating layer onto the nonwoven base web.Therefore, there is no concern about future degradation of an adhesive.The coating is applied onto the embossed face of the web. This is theside of the web that will be installed facing outwardly from a house.

The coating is a mixture of polymer and inorganic particles such ascalcium carbonate. The polymer portion of the coating is typicallypolyethylene or polypropylene, but it could include other polymers aswell. If polyethylene, then the density of the polyethylene is0.915-0.925, or alternatively, 0.918-0.923 grams per cubic centimeter(g/cm3). If polypropylene, then the density is 0.89-0.92 g/cm3, oralternatively, 0.90-0.91 g/cm3. The calcium carbonate is 35-70% byweight of the coating mixture, or alternatively 40-60% by weight.Additional additives in the coating mixture include pigment, UVinhibitors, and processing aids. Importantly, there is no adhesivefraction in the coating mixture. The coating weight of the mixture onthe base web is 30-45 g/m2, or alternatively, 35-40 g/mp2.

The coated nonwoven web is next activated by stretching in order tocreate micropores across and through the coating layer. The coated webmay be activated by stretching with or without heat added to the coatedweb. The stretch may be in the machine direction or cross direction or acombination of both directions. In one example, intermeshing gears areused to stretch the web in the cross-direction in non-uniform fashion.This may result in the stretching in the cross-direction of about 10% orless, or alternatively about 5% or less, or still further alternativelyabout 3% or less. The result is a breathable sheet that is substantiallyimpermeable to liquid water yet permeable to gas/air that flows throughthe pores around the calcium carbonate in the polymer layer.

An important aspect of the entire web being coated on the outside-facingside of the web is the seal of the web to flashing that is taped to theweb around windows and doors and other building openings. The flashingtape adhesive is able to form a continuous and complete seal with thecoated surface of the housewrap. This seal prevents any wicking or otheraccess of water underneath or around the flashing tape. The flashingtape is not adhered to any porous layer or component of the housewrapweb as in other housewrap constructions. Also, the housewrap is pliantand resilient in that a flashing tape may be pressed onto the coatedface of the housewrap, and the texture of the housewrap is able to becompressed to obtain the complete seal. Other housewraps with hardplastic beads applied to the surface of a housewrap are not resilient,so flashing tape applied to such other housewraps may unintentionallyresult in small gaps and crevices around the hard plastic beads that mayenable water or moisture to leak underneath a flashing tape.

Another result of the foregoing processing is a housewrap that has adegree of texture on both sides of the housewrap. In other words, theoval half-bubbles on the coated side also extend outwardly from theopposite, uncoated side of the web. These back-side protrusions are notcoated, but they may assist in creating the gaps or channels when thehousewrap is installed behind a house siding.

Turning now to the drawings, FIG. 1 shows the side of a portion of ahouse 10 having the housewrap 12 mounted on the walls and around thewindows 14 of the house. FIG. 1 is a view of a house 10 during itsconstruction. The housewrap 12 is a barrier film that is wrapped aroundthe house and under siding (not shown) that is mounted over thehousewrap. The housewrap 12 is typically a vertical installation,relative to the ground, on the side of a house 10, although there may beadditional surfaces that are angled with respect to the ground not inthe vertical orientation.

FIG. 1A is a close-up perspective view of a housewrap 15 similar to thehousewrap 12 seen in its installed environment in FIG. 1. FIG. 1Aillustrates the coated, outside of the house facing side of housewrap15. The housewrap 15 has oval half-bubbles 16 and 17 embossed therein.In between the oval half-bubbles 16 and 17 is the compressed portion orchannels 18 of the nonwoven housewrap 15. The embossing pattern in FIG.1A is similar to that illustrated in FIG. 2A described below. There arealternating rows of oval half-bubbles 16 that are oriented on their longaxis 90 degrees from the long axis of the oval half-bubbles 17 in thenext adjacent row. In one example, it is intended that these ovalhalf-bubbles 16 and 17 are oriented about 45 degrees from vertical in avertical installation of the housewrap.

FIG. 1B is a close-up perspective view of a housewrap 180 similar to thehousewrap 12 seen in its installed environment in FIG. 1. FIG. 1Billustrates the uncoated, inside of the house facing side of housewrap180. This inside face of housewrap 180 is opposite the embossed sideseen in FIG. 1A. This housewrap 180 has a flat inside the house facingside when it is embossed but not yet coated and activated. However, asis readily seen in FIG. 1B, the inside face of housewrap 180 doesdisplay some texture. The housewrap 180 inside face shown has ovalhalf-bubble shapes 182 and 184 like on its outside face. There remainsthe flat portion 186 that is a series of channels between the raisedhalf-bubbles 182 and 184. There is shown alternating rows of thehalf-bubble ovals 182 and 184 where half-bubble ovals 182 are orientedon their long axis perpendicular or 90 degrees from the long axis ofoval half-bubbles 184 in the next adjacent rows. As with FIG. 1A, it isintended that these oval half-bubbles 182 and 184 are oriented about 45degrees from vertical in a vertical installation of the housewrap.

FIG. 1C illustrates the side cross-sectional views of two installations150 and 160 of the housewrap 154 as described herein as compared with aprior art flat housewrap 164. In installation 160, a vertical structuralboard 162 has a flat housewrap 164 attached in its outside face. Sidingboards 166 are then overlapped and secured to the structural board 162so that the housewrap 164 is secured in between. During use, theinstallation 160 may have water 168 that builds up between the housewrap164 and the siding 166. The water 168 flows downwardly by gravity andmay dam 170 between the top of a siding board 166 and the housewrap 164.This trapped water 170 may flow sideways and damage windows and doors.The standing water 170 may simply damage the installation 160 generally.On the other hand, installation 150 has the housewrap 154 describedherein installed between a structural board 152 and the siding panel156. The outside face 155 of the housewrap 154 has texture on it asillustrated in FIG. 1A. In the installation 150, therefore, water 158that may seep or form behind the siding 156 is allowed to flowdownwardly by gravity in the channels between the textured half-bubbles.

FIG. 2A illustrates a top view of the outside face of a portion ofhousewrap 20 having oval shaped half-bubbles 22 and 24 embossed thereon.The unembossed, flat portion channels 26 of the housewrap 20 are betweenthe half-bubbles 22 and 24. In FIG. 2A, looking from upper left to lowerright, there are two rows, at about a 45 degree angle, of the ovalhalf-bubbles 22 and 24. The long axes of the oval half-bubbles 22 and 24are oriented perpendicular with respect to each other. Looking fromupper right to lower left, those rows of half-bubbles are rows ofalternating perpendicular ovals 22 and 24. The oval half-bubbles createchannels in the flat surface 26 between the half-bubbles. Because of thethree-dimensional structure of the oval half-bubbles 22 and 24, thosechannels are maintained even after siding is attached over the housewrap20 in installation onto a house. This specific orientation also allowsfor an installer to mount the housewrap 20 in either direction on a wallthereby eliminating inadvertent error during installation.

FIG. 2B is a top view of the outside face of an alternative housewrap 30in which the flat portion channels 38 are configured between multiplesize oval half-bubbles 32, 34 and 36. In this example, the ovalhalf-bubbles 32, 34 and 36 are all generally oriented in theirrespective long axes on 45 degree angles.

FIG. 2C illustrates the outside face of a housewrap 40 having uniformoval half-bubbles 42 creating channels 44 in the flat portion of thehousewrap.

FIG. 2D is a top view of the outside face of a still further housewrap130 having diamond-shaped half-bubbles 132 and 134 embossed thereon. Inbetween the half-bubbles 132 and 134 are the flat portion channels 136.As shown, there are alternating rows of diamond half-bubbles 132 and 134in a substantially symmetrical layout with the long axis of each diamondhalf-bubble 132 and 134 in adjacent perpendicular aspects with respectto each other and approximately 45 degrees from the vertical.

FIG. 2E illustrates the top view of the outside face of housewrap 140having diamond-shaped half-bubbles 142 and oval half-bubbles 144. Thereare adjacent and alternating rows of the diamond half-bubbles 142 andoval half-bubbles 144. Embossed in between the half-bubbles 142 and 144are flat portion channels 146. As shown, the long axis of the diamondhalf-bubbles 142 is perpendicular to the long axis of the ovalhalf-bubbles 144 and are approximately 45 degrees from the vertical.

The examples of housewrap 20, 30, 40, 130 and 140 shown in FIGS. 2A-Erespectively are merely examples of the embossing that may be pressedinto the housewrap. It is alternatively possible that the embossedhalf-bubbles may be other shapes such as square, rectangular, triangularround or other shapes both symmetrical and asymmetrical as long as thepurpose of forming and supporting channels between the embossing isachieved. Also, the size and relative orientation of the respectivehalf-bubbles on a housewrap may be varied. Both symmetric and asymmetricpatterns are possible.

FIG. 3 is a schematic view of the process 50 of coating an embossed web52 with a polymer 54 to create a coated web 64. An uncoated, nonwovenweb 52 is provided that has already been embossed. The web 52 is anonwoven polymer 67 with a flat side 66 and the embossed side 68 tocreate a textured side of the web. The uncoated web 52 is passed betweena nip roller 58 and a chill roll 60 while simultaneously being extrusioncoated with a polymer 54 from an extrusion die 56. The heated liquidpolymer 54 is cooled by the chill roll 60 thereby bonding it to thetextured side 68 of the nonwoven web 52. A strip roll 62 is used toremove the coated web 64 from the chill roll 60. The result is thecoated web 64 with a coating 69 on the textured side 68 of the nonwovenweb 67. A side-effect of the process is the texturing of the uncoatedside 65 of the coated web.

FIG. 4 is a side, cross-sectional view of the coated web 70 having theoval half-bubbles as shown in FIG. 2A that alternate at perpendicularrows with long axis half-bubbles 76 and the width cross-section ofsimilar half-bubbles 78. As shown, channels 75 are shown as the flat,unembossed portion of the web 70. The back, uncoated side 80 of the web70 is shown having some limited amount of texture. The back side 80 isnot flat, but it does not have the height of texture of the coated side74. In production, the back side 80 has a texture height of about25-75%, in one example about 50% of the coated, embossed side 74 of theweb 70.

FIG. 5 is a schematic of the entire process 100 of coating andactivating a web. Moving from left to right in FIG. 5, the processbegins with a roll 102 of embossed, nonwoven film 104. The film 104 isunwound and fed between a nip roll 110 and chill roll 112 while anextrusion die 106 extrudes a polymer coating 108 onto the web 104. Thenow-coated web 116 feeds around a strip roll 114 to an activator 118that stretches the coated film. The activated and coated web 120 is thenwound up on rewind roller 122.

FIG. 6 is a side view of a portion of a building 130 having a sidewall132 covered with the housewrap 134 described herein. As shown, thehousewrap 134 is mounted all around a window 136 in the sidewall 132. Inorder to completely seal around the window 136, flashing tape 138, 140,142 and 144 is adhered to the top surface of the housewrap 134 and tothe sides, top and bottom of the window respectively. The use offlashing is required by local building codes and is a commonconstruction technique in any event.

FIG. 7 illustrates the benefit of using a resilient housewrap 150 asdescribed herein with a flashing tape 160. Specifically, during theinstallation process, a flashing tape 160 coated with adhesive 158 ispressed against the coated surface 156 of the housewrap substrate 150.With this pressure application, the adhesive 158 will adhere to and fillin next to the coated surface 156. Importantly, the housewrap substrate150 is flexible so that it can flatten out under pressure in order toobtain an adhesive seal against both the textured bumps 152 and channels154 on the surface of the housewrap 150. The result is a continuous sealbetween the adhesive 158 and the

EXAMPLE

An embossed web of nonwoven polypropylene fabric of about 100 gm/m2basis weight and about 0.030″ thickness is obtained and extrusion coatedon the embossed side with 34 gm/m2 of a mineral/polymer blend (52%calcium carbonate, 42% low density polyethylene OR polypropylene, 6%additives for UV resistance, and processing aids) at a melt temperatureof 540 deg F. with a matte finish. The coated fabric is then activatedby intermeshing gears (IMG) to provide nonlinear microstretching in thecross-machine direction. The activated web is then printed, dried, andwound into 100-ft rolls. Finished product is tested to assure complianceto desired specifications, per:

ASTM E2273>90% drainage efficiencyASTM E96->5 US Perms water vapor transmission rateAATCC 127-22 55 cm hydrostatic head water pressure resistanceASTM D882->40 lbs/inch tensile breaking strengthASTM E2178-<0.02 liters/sec air permeance

The foregoing performance tests indicate a superior housewrapconstruction.

Other embodiments of the present invention will be apparent to thoseskilled in the art from consideration of the specification. It isintended that the specification and figures be considered as exemplaryonly, with a true scope and spirit of the invention being indicated bythe following claims.

1. A drainage housewrap comprising: a nonwoven base web having athree-dimensional pattern pressed therein to form channels on a surfaceof the base web, a coating bonded by extrusion coating to the surface ofthe base web after the three-dimensional pattern is pressed in it,wherein the coating comprises a mixture of a polymer and calciumcarbonate particles, and further wherein the coated base web isactivated by mechanical stretching of the coated base web in order tocreate micropores in the coating on the base web, and the thickness ofthe coated base web is from 0.015 to 0.05 inches; and wherein thehousewrap is impermeable to water but permeable to water vapor and air.2. A drainage housewrap as described in claim 1, wherein thethree-dimensional pattern pressed into the base web creates two sets ofchannels that are substantially perpendicular from each other.
 3. Adrainage housewrap as described in claim 1, wherein the polymer portionof the coating comprises polyethylene.
 4. A drainage housewrap asdescribed in claim 1, wherein the polymer portion of the coatingcomprises polypropylene.
 5. A drainage housewrap as described in claim1, wherein the three-dimensional pattern is in the shape of ovalhalf-bubbles.
 6. A drainage housewrap as described in claim 5, whereinthe oval half-bubbles are positioned in alternating rows such that along axis of each row of oval half-bubbles is perpendicular to the longaxis of each adjacent row of oval half-bubbles.
 7. A drainage housewrapas described in claim 1, wherein the calcium carbonate comprises 35-70%by weight of the coating.
 8. A drainage housewrap as described in claim1, further comprising flashing tape adhered to the coated side of thecoated base web, whereby there is a continuous and complete seal formedbetween the flashing tape and the coated base web.